Systems, assemblies and methods for spinal derotation

ABSTRACT

Systems, assemblies, components and methods for correcting alignment of one or more vertebrae of a spine are provided. A first elongate derotator member includes a first elongate element having a first proximal end portion and a first distal end portion. The first distal end portion is releasably engageable with a first implant implanted in one of the vertebrae. A second elongate derotator member comprising a second elongate element is releasably engageable with a second implant implanted in the same vertebra. A transverse member is engageable with the first and second elongate elements. A first channel extends axially through the first elongate element and a second channel extends axially through the second elongate element such that a proximal end portion of the first implant can be accessed from a proximal end portion of the first elongate element by inserting a tool through the first channel and a proximal end portion of the second implant can be accessed from a proximal end portion of the second elongate element by inserting the tool or another tool through the second channel.

CROSS-REFERENCE

This application is continuation of co-pending application Ser. No.14/875,414, filed Oct. 5, 2015, which is a division of application Ser.No. 13/777,998, filed Feb. 26, 2013, now U.S. Pat. No. 9,179,957, issuedNov. 10, 2015, which is a continuation-in-part of application Ser. No.13/717,599 filed Dec. 17, 2012, now U.S. Pat. No. 9,155,581, issued Oct.13, 2015, which is a continuation-in-part of application Ser. No.13/570,374, filed Aug. 9, 2012, now U.S. Pat. No. 9,572,598, issued Feb.21, 2017, which applications and patents are hereby incorporated herein,in their entireties, by reference thereto, and to which applications weclaim priority under 35 USC § 120. This application also referencesapplication Ser. No. 13/717,565 filed Dec. 17, 2012, which applicationis hereby incorporated herein, it its entirety, by reference thereto.

FIELD OF THE INVENTION

The present invention relates to the field of orthopedic surgery, inparticular to devices, systems and assemblies for stabilizing and/orfixing bones and/or joints in a patient. More particularly, the presentinvention relates to instruments, assemblies and methods for correctingspinal alignment.

BACKGROUND OF THE INVENTION

The fixation and/or stabilization of bones and/or bone fragments is/arecommonly required by orthopedic surgeons to treat injuries such asfractures or disease. To accomplish this, the bones/bone fragments canbe joined by a rod, plate or the like, which is fixed to the bones/bonefragments via fasteners such as screws, pins or the like. The connectionby the rod(s), plate(s) or the like maintains the bones/bone fragmentsin a desired orientation and/or at desired spacings, positions, etc.

In spinal surgery, it is often necessary to secure various implants tothe vertebrae and interconnect the vertebrae by attaching one or morerods or plates to the implants. Due to the complex curvature of thespine, as well as irregularities of the same that often need to betreated, it is often difficult to align a rod or plate with all of theimplants/fasteners fixed to the various vertebrae to be connected viathe rod or plate. In some surgeries, it is necessary to span multiplevertebrae of the spine with rods that provide stabilizing forces to thevertebrae to help maintain the desired orientations of the vertebrae tomaintain a desired curvature in the spine. In these instances,repositioning of multiple vertebrae is often required, often byrepositioning relative to multiple planes, in order to achieve thedesired alignment of the vertebrae and correct the curvature of thespine/deformity being treated.

There is a need for instruments, assemblies and procedures to facilitatesuch complex realignment procedures. There is a need for instrument,assemblies and methods that not only can perform these complexprocedures, but which also facilitate the ability to more readily attachthe instruments when the vertebrae are out of alignment and where itwould be otherwise difficult or impossible, using conventionalinstrumentation to interconnect instrumentation being used because ofextreme malalignment of the vertebrae being treated.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a system forcorrecting alignment of one or more vertebrae of a spine is provided,including: the first elongate derotator member comprising a firstelongate element having a first proximal end portion and a first distalend portion, the first distal end portion being releasably engageablewith a first implant implanted in one of the vertebrae; a secondelongate derotator member comprising a second elongate element having asecond proximal end portion and a second distal end portion, said seconddistal end portion being releasably engageable with a second implantimplanted in the one of the vertebrae; and a transverse memberengageable with the first and second proximal end portions of the firstand second elongate elements; wherein a first channel extends axiallythrough the first elongate element and a second channel extends axiallythrough the second elongate element such that a proximal end portion ofthe first implant can be accessed from a proximal end portion of thefirst elongate element by inserting a tool through the first channelwhen the first elongate derotator member is engaged with the firstimplant and a proximal end portion of the second implant can be accessedfrom a proximal end portion of the second elongate element by insertingthe tool or another tool through the second channel when the secondelongate derotator member is engaged with the second implant.

In at least one embodiment, the proximal end portion of the firstimplant can be accessed from the proximal end portion of the firstelongate element by inserting a tool through the first channel when thetransverse member is engaged with the first proximal end portion of thefirst elongate element and wherein the proximal end portion of thesecond implant can be accessed from the proximal end portion of thesecond elongate element by inserting the tool or another tool throughthe second channel when the transverse member is engaged with theproximal end portion of the second elongate element.

In at least one embodiment, the first elongate derotator member furthercomprises a third elongate element slidable over the first elongateelement, wherein the third elongate element is distally slidablerelative to the first elongate element to lock engagement of the firstdistal end portion with the first implant; and wherein the secondelongate derotator member further comprises a fourth elongate elementslidable over the second elongate element, wherein the fourth elongateelement is distally slidable relative to the second elongate element tolock engagement of the second distal end portion with the secondimplant.

In at least one embodiment, the system further includes the first andsecond implants.

In at least one embodiment, the system further includes: a first linkingmember configured to engage the transverse member with the firstproximal end portion of the first elongate element; and a second linkingmember configured to engage the transverse member with the secondproximal end portion of the second elongate element; wherein the firstlinking member is releasably engageable with the first proximal endportion of the first elongate element and the second linking member isreleasably engageable with the second proximal end portion of the secondelongate element.

In at least one embodiment, the first linking member comprises a distalend portion having a first longitudinal axis aligned with a longitudinalaxis of the first elongate member when the first linking member isengaged with the first elongate member, and a proximal end portionconfigured to engage with the transverse member, the proximal endportion of the first linking member having a second longitudinal axisoffset from the first longitudinal axis; and the second linking membercomprises a distal end portion having a third longitudinal axis alignedwith a longitudinal axis of the second elongate member when the secondlinking member is engaged with the second elongate member, and aproximal end portion configured to engage with the transverse member,the proximal end portion of the second linking member having a fourthlongitudinal axis offset from the third longitudinal axis.

In at least one embodiment, the system further includes a first balljoint interconnecting the proximal end portion of the first linkingmember with the distal end portion of the first linking member; and asecond ball joint interconnecting the proximal end portion of the secondlinking member with the distal end portion of the second linking member.

In at least one embodiment, the system further includes: a thirdelongate derotator member comprising a third elongate element having athird proximal end portion and a third distal end portion, the thirddistal end portion being releasably engageable with a third implantimplanted in a second one of the vertebrae; a fourth elongate derotatormember comprising a fourth elongate element having a fourth proximal endportion and a fourth distal end portion, the fourth distal end portionbeing releasably engageable with a fourth implant implanted in thesecond one of the vertebrae; and a second transverse member engageablewith the third and fourth proximal end portions of the third and fourthelongate elements; wherein a third channel extends axially through thethird elongate element and a fourth channel extends axially through thefourth elongate element such that a proximal end portion of the thirdimplant can be accessed from a proximal end portion of the thirdelongate element by inserting the tool or another tool through the thirdchannel when the third elongate derotator member is engaged with thethird implant and a proximal end portion of the fourth implant can beaccessed from a proximal end portion of the fourth elongate element byinserting the tool or another tool through the fourth channel when thefourth elongate derotator member is engaged with the fourth implant.

In at least one embodiment, the system further includes an interlevellinking assembly extending between and engaged with the first elongatederotator member and the third elongate derotator member.

In another aspect of the present invention, a system for correctingalignment of one or more vertebrae of a spine includes: a first elongatederotator member comprising a first elongate element having a firstcentral longitudinal axis, a first proximal end portion and a firstdistal end portion, the first distal end portion being releasablyengageable with a first implant implanted in one of the vertebrae; asecond elongate derotator member comprising a second elongate elementhaving a second central longitudinal axis, a second proximal end portionand a second distal end portion, the second distal end portion beingreleasably engageable with a second implant implanted in the one of thevertebrae; and a transverse member engageable with the first and secondproximal end portions of the first and second elongate elements; whereinthe first central longitudinal axis is substantially aligned with alongitudinal axis of a head of the first implant when the first elongatederotator member is engaged with the first implant, and wherein thesecond central longitudinal axis is substantially aligned with alongitudinal axis of a head of the second implant when the secondelongate derotator member is engaged with the second implant.

In at least one embodiment, the first elongate derotator member furthercomprises a third elongate element slidable over the first elongateelement, wherein the third elongate element is distally slidablerelative to the first elongate element to lock engagement of the firstdistal end portion with the first implant; and the second elongatederotator member further comprises a fourth elongate element slidableover the second elongate element, wherein the fourth elongate element isdistally slidable relative to the second elongate element to lockengagement of the second distal end portion with the second implant.

In at least one embodiment, the system further includes the first andsecond implants.

In at least one embodiment, the system further includes: a first linkingmember configured to engage the transverse member with the firstproximal end portion of the first elongate element; and a second linkingmember configured to engage the transverse member with the secondproximal end portion of the second elongate element; wherein the firstlinking member is releasably engageable with the first proximal endportion of the first elongate element and the second linking member isreleasably engageable with the second proximal end portion of the secondelongate element.

In at least one embodiment, the first linking member is attachable toand detachable from the first elongate element without the use of tools,and the second linking member is attachable to and detachable from thesecond elongate element without the use of tools.

In at least one embodiment, the first linking member comprises a firstreleasable engagement member movable between an engaged position and adisengaged position and vice versa, and when the first linking member ismounted on the first elongate element and the first releasableengagement member is in the engaged position, the first releasableengagement member engages a first mating engagement element of the firstelongate element, thereby preventing dismounting of the first linkingmember from the first elongate element; and the second linking membercomprises a second releasable engagement member movable between anengaged position and a disengaged position and vice versa, and when thesecond linking member is mounted on the second elongate element and thesecond releasable engagement member is in the engaged position, thesecond releasable engagement member engages a second mating engagementelement of the second elongate element, thereby preventing dismountingof the second linking member from the second elongate element.

In at least one embodiment, the first and second releasable engagementmembers are respectively prebiased to the engaged position.

In at least one embodiment, the first linking member comprises a firstdistal end portion having a first longitudinal axis aligned with alongitudinal axis of the first elongate member when the first linkingmember is engaged with the first elongate member, and a first proximalend portion configured to engage with the transverse member, theproximal end portion of the first linking member having a secondlongitudinal axis offset from the first longitudinal axis; and thesecond linking member comprises a second distal end portion having athird longitudinal axis aligned with a longitudinal axis of the secondelongate member when the second linking member is engaged with thesecond elongate member, and a second proximal end portion configured toengage with the transverse member, the second proximal end portion ofthe second linking member having a fourth longitudinal axis offset fromthe third longitudinal axis.

In at least one embodiment, the system further includes: a first balljoint interconnecting the first proximal end portion of the firstlinking member with the first distal end portion of the first linkingmember; and a second ball joint interconnecting the second proximal endportion of the second linking member with the second distal end portionof the second linking member.

In at least one embodiment, the first linking member comprises a firstdistal end portion, a first proximal end portion and a first ball jointinterconnecting the first distal end portion and the first proximal endportion, wherein the first proximal end portion is configured toreleasably engage with the transverse member and the first distal endportion is configured to releasably engage with the first elongateelement; and the second linking member comprises a second distal endportion, a second proximal end portion and a second ball jointinterconnecting the second distal end portion and the second proximalend portion, wherein the second proximal end portion is configured toreleasably engage with the transverse member and the second distal endportion is configured to releasably engage with the second elongateelement.

In at least one embodiment, the system further includes: a thirdelongate derotator member comprising a third elongate element having athird proximal end portion and a third distal end portion, the thirddistal end portion being releasably engageable with a third implantimplanted in a second one of the vertebrae; a fourth elongate derotatormember comprising a fourth elongate element having a fourth proximal endportion and a fourth distal end portion, the fourth distal end portionbeing releasably engageable with a fourth implant implanted in thesecond one of the vertebrae; and a second transverse member engageablewith the third and fourth proximal end portions of the third and fourthelongate elements.

In at least one embodiment, the system further includes an interlevellinking assembly extending between and engaged with the first elongatederotator member and the third elongate derotator member.

In another aspect of the present invention, a system for correctingalignment of one or more vertebrae of a spine includes: a first elongatederotator member comprising a first elongate element having a firstcentral longitudinal axis, a first proximal end portion and a firstdistal end portion, the first distal end portion being releasablyengageable with a first implant implanted in one of the vertebrae; afirst linking member comprising a first proximal end portion and a firstdistal end portion; a second elongate derotator member comprising asecond elongate element having a second central longitudinal axis, asecond proximal end portion and a second distal end portion, the seconddistal end portion being releasably engageable with a second implantimplanted in the one of the vertebrae; a second linking membercomprising a second proximal end portion and a second distal endportion; and a transverse member engageable with the first and secondlinking members; wherein the first distal end portion of the firstlinking member is configured to engage the first proximal end portion ofthe first elongate derotator member, the first proximal end portion ofthe first linking member is configured to releasably engage with thetransverse member, and the first proximal end portion of the firstlinking member is articulatable in three dimensions relative to thefirst distal end portion of the first linking member when the firstdistal end portion of the first linking member is fixed relative to thefirst elongate derotator member; and wherein the second distal endportion of the second linking member is configured to engage the secondproximal end portion of the second elongate derotator member, the secondproximal end portion of the second linking member is configured toreleasably engage with the transverse member, and the second proximalend portion of the second linking member is articulatable in threedimensions relative to the second distal end portion of the secondlinking member when the second distal end portion of the second linkingmember is fixed relative to the second elongate derotator member.

In at least one embodiment, the first proximal end portion of the firstlinking member further comprises a first driver actuatable to releasablylock the transverse member in engagement with the first linking memberand to releasably lock the first proximal end portion of the firstlinking member relative to the first distal end portion of the firstlinking member, thereby preventing articulation of the first proximalend portion of the first linking member relative to the first distal endportion of the first linking member; and the second proximal end portionof the second linking member further comprises a second driveractuatable to releasably lock the transverse member in engagement withthe second linking member and to releasably lock the second proximal endportion of the second linking member relative to the second distal endportion of the second linking member, thereby preventing articulation ofthe second proximal end portion of the second linking member relative tothe second distal end portion of the second linking member.

In another aspect of the present invention, a derotator member useful ina system for correcting alignment of one or more vertebrae of a spineincludes: a first elongate element having a first proximal end portionand a first distal end portion, the first distal end portion beinglongitudinally split into at least two split portions configured toreleasably engage with an implant implanted in one of the vertebrae; anda second elongate element slidable over the first elongate element, thesecond elongate element having a second proximal end portion and asecond distal end portion; wherein the second distal end portion isslidable over at least part of the split portions thereby preventing thesplit portions from deforming away from one another; and wherein thedistal end portion is slidable away from the split portions to an extentto allow the split portions to deform away from one another.

In at least one embodiment, the distal end portion is hollow, thederotator member further comprising protrusions extending inwardly fromthe split portions, the protrusions configured to be inserted intofemale mating features on a head of the implant to engage the implant.

In at least one embodiment, the first elongate element comprises twosplit portions and each the split portion comprises two protrusions.

In at least one embodiment, the first elongate element is hollow,allowing a tool to be inserted through a proximal opening thereof in theproximal end portion to engage a portion of the implant when the distalend portion is engaged with the implant.

In at least one embodiment, the derotator member further includes akeyed outer surface at the proximal end portion of the first elongatemember, the keyed outer surface configured to engage with a mating keyedinner surface of a linking member to prevent rotation of the linkingmember relative to the first elongate member.

In at least one embodiment, the derotator member further includes arecess in an outer surface of the proximal end portion of the firstelongate member, the recess configured to engage with a locking featureof a linking member to prevent detachment of the linking member from thefirst elongate member when the locking feature is engaged in the recess.

In at least one embodiment, the keyed outer surface allows multipleangular orientations of the linking member relative to a transverse axisof the first elongate member.

In at least one embodiment, the derotator member is provided incombination with a linking member engaged with the first elongatemember.

In another aspect of the present invention, a linking member for linkinga derotator member to a transverse member in a system useful forcorrecting alignment of one or more vertebrae of a spine includes: adistal end portion and a proximal end portion; the distal end portioncomprising a first opening configured to receive and releasably engagewith a proximal end portion of the derotator member; the proximal endportion comprising a second opening configured to receive and releasablyengage with the transverse member, wherein the second opening isoriented transverse to an orientation of the first opening; a surfacedefining the first opening comprising a keyed inner surface configuredto maintain an angular orientation of the linking member relative to atransverse axis of the derotator member when the linking member isengaged with the derotator member; a locking element movable from alocked configuration to an unlocked configuration and vice versa,wherein, when in the locked configuration, the locking element extendsinto the first opening; and wherein the proximal end portion isarticulatable relative to the distal end portion in three dimensions.

In at least one embodiment, the linking member further includes anunlocking actuator actuatable to move the locking element from thelocked configuration to the unlocked configuration.

In at least one embodiment, the locking element is biased to the lockedconfiguration, so that when the actuator is not being actuated, thelocking element is in the locked configuration.

In at least one embodiment, the keyed inner surface is multifaceted andpermits selection from multiple different angular orientations of thelinking member relative to the transverse axis of the derotator member,wherein the linking member is maintained in a selected angularorientation once engaged with the derotator member at the selectedangular orientation.

In at least one embodiment, the linking member further includes a driveractuatable to releasably lock the transverse member in engagement withthe linking member after insertion of the transverse member into thesecond opening, and to releasably lock the first end portion of thelinking member relative to the distal end portion of the linking member,thereby preventing articulation of the proximal end portion relative tothe distal end portion.

In at least one embodiment, the linking member is provided incombination with a handle having first and second ends, wherein thesecond end of the handle is configured to mate with the driver and, uponmating with the driver, the handle is manipulatable to operate thedriver.

In at least one embodiment, the linking member further includesprotrusions extending into the second opening, the protrusion configuredto increase friction with the transverse member upon receipt andengagement of the transverse member by the proximal end portion.

In at least one embodiment, the linking member further includes a balljoint interlinking the proximal end portion and the distal end portionand facilitating articulation of the proximal end portion relative tothe distal end portion.

In at least one embodiment, the linking member is provided incombination with a transverse member and a derotator member, wherein thedistal end portion of the linking member is engaged with and fixedrelative to the derotator member and the transverse member is receivedin the proximal end portion, while the proximal end portion and thetransverse member are free to articulate in three dimensions relative tothe distal end portion.

In at least one embodiment, the linking member is provided incombination with a transverse member and a derotator member, wherein thedistal end portion of the linking member is engaged with and fixedrelative to the derotator member and the proximal end portion is fixedrelative to the transverse member, wherein the transverse member is andthe proximal end portion are fixed relative to the distal end portion.

In at least one embodiment, the linking member is provided incombination with a handle having first and second ends, wherein thesecond end of the handle is configured to mate with a driver configuredto drive locking of the transverse member and the proximal end portionrelative to the distal end portion and, upon mating with the driver, thehandle is manipulatable to operate the driver; and wherein the first endof the handle is configured to be inserted into a proximal opening ofthe derotator member and, upon insertion into the proximal opening, thehandle is manipulatable to drive movement of the derotator member andtransverse member.

In another aspect of the present invention, an interlevel linkingassembly for linking at least two derotator members on one side of aspine in a system useful for correcting alignment of one or morevertebrae of the spine includes: an elongate interlink member having alength sufficient to span the locations of all of the derotator membersto be linked; and a plurality of interlink clamps configured to securelyengage the derotator members, each the interlink clamp comprising: clampjaws configured to releasably engage the derotator member; a shaftextending from the clamp jaws; and a driver actuatable on an end of theshaft extending away from the clamp jaws to actuate the clamp jaws toclamp down on the derotator member; wherein the shaft has sufficientlength to extend through an opening in the elongate interlink member andengage the driver on one side of the elongate interlink member while theclamp jaws are positioned on an opposite side of the elongate interlinkmember.

In at least one embodiment, the interlink clamps are configured to snapfit onto the respective derotator members, after which further clampingforce is applicable by actuation of the drivers.

In at least one embodiment, the interlevel linking assembly furtherincludes a base adjacent the clamp jaws, wherein the driver cooperateswith the base to drive clamping action of the clamp jaws.

In at least one embodiment, the base is selectable from a plurality ofbases each having a different length, and wherein different length basesare selectable to compensate for varying distances between the elongateinterlink member and the derotator members.

In at least one embodiment, the elongate interlink member comprises aunitary plate.

In at least one embodiment, the unitary plate comprises a slot extendinglongitudinally therein, the slot having a length sufficient to span thelocations of all of the derotator members to be linked.

In at least one embodiment, the interlink clamps are slidable in theslot, prior to fixation of the interlink clamps.

In at least one embodiment, the interlink clamps are rotatable in theslot, within a controlled range of rotation, prior to fixation of theinterlink clamps.

In at least one embodiment, the elongate interlink member comprises aplurality of linked plates, the linked plates being axially rotatablerelative to one another, within a controlled range of rotation.

In at least one embodiment, at least one of the linked plates comprisesa slot extending longitudinally therein, and wherein one of theinterlink clamps is slidable in each slot, prior to fixation thereof.

In at least one embodiment, the interlevel linking assembly is fixedlyclamped to the plurality of derotator members.

In at least one embodiment, the interlevel linking assembly is providedin combination with a second plurality of the derotator members on anopposite side of the spine, interconnected to the plurality of derotatormembers by respective transverse members.

In another aspect of the present invention, a system for correctingalignment of one or more vertebrae of a spine includes: a plurality ofpairs of elongate derotator members, each the member comprising aelongate element having a longitudinal axis, a proximal end portion anda distal end portion, the distal end portion being releasably engageablewith an implant implanted in one of the vertebrae in a manner that thelongitudinal axis is substantially aligned with a longitudinal axis ofthe implant; wherein a first of each the pair is located on a first sideof the spine and engageable with an implant implanted on a first side ofthe vertebra and a second of each pair is respectively located on asecond side of the spine and engageable with an implant on the samevertebra on the second side of the spine, and wherein each the derotatormember on the first side of the spine is adapted to be engaged to adifferent vertebra from the vertebra that each of the other derotatormembers on the first side of the spine is adapted to be engaged to; aplurality of interlink members with one of the interlink membersattached to each of the derotator members, respectively; a plurality oftransverse members with one of the transverse members attached to eachthe pair of derotator members through the interlink members,respectively, wherein the transverse members connect to the interlinkmembers at locations offset from the longitudinal axes of the elongateelements; and at least one handle attached to one of a proximal openingof one of the elongate elements or a proximal end portion of one of theinterlink members.

In at least one embodiment, the system further includes an interlevellinking assembly attached directly to a plurality of the derotatormembers on one of the first and second sides of the spine.

In another aspect of the present invention, a method of assembling asystem for correcting alignment of a spinal column of a patientincludes: engaging a distal end portion of respective first and secondderotation members to respective ones of first and second implantsimplanted in a vertebra of the spinal column on opposite sides of thespinal column; engaging a first interlink member with a proximal endportion of the first derotation member and engaging a second interlinkmember with a proximal end portion of the second derotation member;engaging a transverse member with proximal end portions of the first andsecond interlink members, at locations offset from longitudinal axes ofthe first and second derotation members, respectively; and manipulatingat least one member of the system to align the spinal column.

In at least one embodiment, the method further includes engaging atleast one handle with at least one location selected from a proximal endportion of one of the derotation members and a proximal end portion ofone of the interlink members, such that the handle is substantiallyaligned with the longitudinal axis of the respective derotation memberor proximal end portion of the interlink member; and wherein themanipulating at least one member includes manipulating the at least onehandle.

In at least one embodiment, the method further includes implanting thefirst and second implants prior to the engaging a distal end portion ofrespective first and second derotation members to respective ones offirst and second implants implanted in a vertebra of the spinal columnon opposite sides of the spinal column.

In at least one embodiment, the method further includes engaging firstand second elongate stabilization elements to the first and secondimplants, respectively, after the manipulating to provide post-operativestabilization.

In at least one embodiment, the method further includes: engaging adistal end portion of respective third and fourth derotation members torespective ones of third and fourth implants implanted in a secondvertebra of the spinal column on opposite sides of the spinal column;engaging a third interlink member with a proximal end portion of thethird derotation member and engaging a fourth interlink member with aproximal end portion of the fourth derotation member; and engaging asecond transverse member with proximal end portions of the third andfourth interlink members, at locations offset from longitudinal axes ofthe third and fourth derotation members, respectively.

In at least one embodiment, the method further includes engaging aninterlevel linking assembly to adjacent ones of the derotation memberson one side of the spinal column.

In at least one embodiment, the method further includes inserting a toolthrough a longitudinally extending opening in one of the derotatormembers and performing an operation on the implant that the one of thederotator members is engaged with, from a location proximal of aproximal end the one of the derotator members.

In at least one embodiment, the operation causes a head of the implantto establish a selectable degree of cold welding with a stabilizationmember received by the implant.

In at least one embodiment, the operation causes a selectable degree ofcold welding between a head and a shaft of the implant.

In at least one embodiment the selectable amount of cold welding by theimplant with the stabilization member and the selectable amount of coldwelding between the head and the shaft of the implant occur during thesame operation.

In at least one embodiment, the operation fixes a stabilization memberreceived by the implant, relative to the implant. the engagement of thedistal portion comprises pressing the derotator member against theimplant to deform a distal opening of the derotator member outwardly andsnap fitting the distal portion to the implant.

In at least one embodiment, the method further includes sliding a sleevedistally over the distal portion after the snap fitting to preventoutward deformation of the distal opening.

In at least one embodiment, the engagement of the distal portioncomprises engaging inwardly extending protrusions at the distal portionin recesses in the implant.

In at least one embodiment, the method further includes sliding a sleevedistally over the distal portion after engaging the protrusions in therecesses to prevent escape of the protrusions from the recesses.

In at least one embodiment, the proximal end portions of the interlinkmembers are three-dimensionally adjustable relative to the respectivederotator members that the interlink members are engaged to, the methodcomprising three-dimensionally adjusting at least one of the proximalend portions to align with the transverse member for engagementtherewith.

In at least one embodiment, the method further includes locking theproximal end portions relative to the respective derotator members,after engaging the transverse member, to prevent articulation of theproximal end portion and the transverse member relative to the derotatormember.

In at least one embodiment, the method further includes axially rotatinga portion of the interlevel linking assembly relative to another portionof the interlevel linking assembly to better conform to variances inorientations of the derotator members.

These and other features of the present invention will become apparentupon reading the detailed description of the systems, assemblies,components and methods below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a pair of elongate derotator members linked or engaged witha transverse member by use of linking members according to an embodimentof the present invention.

FIG. 2A is an isolated, plan view of one of the derotator members shownin FIG. 1.

FIG. 2B is an isolated view of an inner elongate element of thederotator member of FIG. 2A.

FIG. 2C is an isolated view of an outer element that is slidablyreceivable over the element shown I FIG. 2B.

FIG. 2D is a view of the derotator member of FIG. 2A in an unlockedconfiguration.

FIG. 2E is a detailed view of the portion of FIG. 2D indicated withincircle 2E.

FIG. 3A is an isolated, perspective view of a linking member, accordingto an embodiment of the present invention.

FIG. 3B shows the linking member of FIG. 3A engaged with the derotatormember of FIG. 2A.

FIG. 3C is a cross sectional view of FIG. 3A taken along line 3C-3C.

FIG. 3D is a partial longitudinal sectional view of the linking memberof FIG. 3A.

FIG. 4 is a longitudinal sectional view of an implant according to anembodiment of the present invention.

FIG. 5 is a partial view showing locking of a derotator member to animplant according to an embodiment of the present invention.

FIG. 6A is a perspective view of an interlevel linking assemblyaccording to an embodiment of the present invention.

FIG. 6B is a perspective view of the elongate interlink member of FIG.6A.

FIG. 6C is a perspective view of an elongate link member according toanother embodiment of the present invention.

FIG. 6D is a longitudinal sectional view of the elongate link member ofFIG. 6C.

FIG. 6E is an exploded view of a clamp shown in FIG. 6A.

FIG. 6F is a longitudinal sectional view of a clamp shown in FIG. 6A.

FIG. 6G illustrates clamps of varying lengths according to an embodimentof the present invention.

FIG. 6H is a perspective view of a clamp loosely engaged in an (partialview of) an elongate link member according to an embodiment of thepresent invention.

FIG. 6I is a cross-sectional view of FIG. 6H taken along line 6I-6I.

FIG. 7 is a plan view of a handle according to an embodiment of thepresent invention.

FIG. 8A illustrates a system comprising a plurality of the assembliesshown in FIG. 1, according to an embodiment of the invention.

FIG. 8B illustrates the system of FIG. 8A interlinked by an interlevellinking assembly according to an embodiment of the present invention.

FIGS. 9A-9C illustrate systems having various handle installationarrangements, according to various embodiments of the present invention.

FIGS. 10A-10I illustrate a method of assembling the assembly of FIG. 1to establish derotator triangulation, according to an embodiment of thepresent invention.

FIG. 11 illustrates insertion of a tool through a proximal end openingof a derotator member to access and implant and perform an operationthereon, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Before the present instruments, assemblies and methods are described, itis to be understood that this invention is not limited to particularembodiments described, as such may, of course, vary. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting, since the scope of the present invention will be limited onlyby the appended claims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassedwithin the invention. The upper and lower limits of these smaller rangesmay independently be included or excluded in the range, and each rangewhere either, neither or both limits are included in the smaller rangesis also encompassed within the invention, subject to any specificallyexcluded limit in the stated range. Where the stated range includes oneor both of the limits, ranges excluding either or both of those includedlimits are also included in the invention.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present invention, the preferred methodsand materials are now described. All publications mentioned herein areincorporated herein by reference to disclose and describe the methodsand/or materials in connection with which the publications are cited.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to “amember” includes a plurality of such members and reference to “thehandle” includes reference to one or more handles and equivalentsthereof known to those skilled in the art, and so forth.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present invention isnot entitled to antedate such publication by virtue of prior invention.Further, the dates of publication provided may be different from theactual publication dates which may need to be independently confirmed.

Spinal derotation instrumentation is provided to carry out one or morederotation maneuvers on one or more vertebrae of a patient's spine tocorrect or improve the orientation of the one or more vertebrae to moreclosely achieve the normal curvature of the spine. For each of at leastone vertebra, a pair of derotation posts are respectively attached to apair of spinal implants implanted in the vertebra on opposite sides ofthe vertebra. For each pair of derotation posts connected, a linkingmember is installed to connect the pair. One or more handles installedon and extending from the derotation posts can then be grasped and usedto apply torque to the posts to reposition the vertebra. Posts connectedto multiple vertebrae can be linked together and rotated in unison.Alternatively, vertebrae can be independently rotated. Still further,groups of posts on multiple vertebrae can be linked, with still one ormore vertebrae having posts attached thereto remaining independent forindependent rotation thereof.

Referring now to FIG. 1, a pair of elongate derotator members 10 areshown linked or engaged with a transverse member 40 by use of linkingmembers 30 according to an embodiment of the present invention. FIG. 2Ais an isolated, plan view of one of the derotator members 10 shown inFIG. 1. Derotator member 10 includes an inner elongate element 12, asshown in isolation in FIG. 2B. Inner elongated element 12 is typicallyformed as a rigid tube with split portions 14 being formed at a distalend thereof and forming the distal end portion of the element 12. Neckedor otherwise narrowed portions 14N interconnect the split portions 14with the integral tubular portion 13 of element 12. This provides splitportions 14 with resilient flexibility so that they can deform away fromone another and then spring back to the restating configuration shown inFIG. 2B, as will be described in greater detail below. Protrusions 14Pextend inwardly from distal end portions of split portions 14.Protrusions 14P (see the detail view of FIG. 2E) are configured to beinserted into female mating features on a head of an implant to engagethe implant, as described in more detail below. Although two splitportions 14 as shown are preferred, the invention is not so limited, astwo, three or even more split portions could be provided to function ina same or similar manner. Likewise, it is preferred that fourprotrusions 14P, two on each split portion are provided, although moreor fewer could be used.

Element 12 is hollow along its interior length and includes a proximalend opening 16P that permits a tool to be inserted through the element12 from opening 16P to extend to the distal end portion of the elementand perform an operation on an implant (such as a pedicle screw or otherimplant) engaged by the split portions 14. The proximal end portion ofelement 12 includes a keyed outer surface 16K configured to engage andmate with a mating keyed inner surface 30M (see FIG. 3A) of linkingmember 30 to prevent rotation of the linking member 30 relative to theelongate member 12/derotator member 10. As shown, keyed surface 16K is amultifaceted, polygonal configuration, although other polygonal as wellas other multifaceted configurations could be substituted. It ispreferred that the keyed surface 16K and mating surface 30M areconfigured so that linking member 30 as be engaged with elongate member12 in more than one orientation, where the different orientations areachieved by rotating the linking member about the longitudinal axis L-Lrelative to the elongate member. Thus, the keyed outer surface allowsmultiple angular orientations of linking member 30 relative to atransverse axis T-T of the elongate member 12/derotator member 10. Ineach different selectable orientational position, the linking membermating surface 30M mates with key surface 16K when linking member 30 ismounted on the proximal end portion of element 12 and thereafterprevents rotation of the linking member 30 relative to element 12 aboutaxis L-L. A recessed locking feature 16R such as a recess, groove orother equivalent structure is provided to cooperate with a lockingfeature of linking member 30 to prevent the linking member 30 frommoving axially relative to element 12 along axis L-L after engagement ofthe linking member with the element 12, and thus preventing inadvertentdetachment of the linking member from elongate member 12 when thelocking feature of the linking member 30 is engaged in recessed lockingfeature 16R.

FIG. 2C is an isolated view of an outer element 18 that is slidablyreceived over element 12 of derotator member 10. Element 18 ispreferably a rigid tube having a length less than the length of element12 so that it can be slid between an engaged or locked position(illustrated in FIG. 2A) and a disengaged or unlocked position(illustrated in FIG. 2D). In the disengaged position shown in FIG. 2D,all or a major portion of the split portions 14 extend distal of thedistal end of element 18. This allows split portions 14 to deform awayfrom one another as the distal end of element 12/portions 14 contact theproximal end of an implant 200 to be engaged, as illustrated in FIG. 2D.The distal end(s) of element 12/portions 14 may be beveled inwardly tofacilitate driving the portions away from each other as they are drivenagainst the distal end edge surfaces of the implant 200. As thederotator member 10 is driven further distally relative to the implant200, the protrusions 14P pass over the external surface of a distalportion of the implant 200 until they reach the level of female matingfeatures 202 (see Fig. **) of the implant 200. The portions 14resiliently move toward one another (driven by the spring forcedeveloped during the deformation away from one another) thereby engagingprotrusions 14P in mating features 202. At this stage, element/sleeve 18is next slid distally relative to element 12, from a position such asillustrated in FIG. 2A to a position shown in FIG. 2D, where the distalend portion of element 18 surrounds substantially all of the splitportions 14, thereby preventing the ability of split portions 14 todeform away from one another, and ensuring that protrusions 14P remainengaged in mating features 202, thereby locking derotator member 10 toimplant 200. Alternatively, split portions 14 can be configured suchthat, in their unbiased positions, they extend slightly apart from oneanother, such that the split portions 14 and protrusions 14P can passover the distal end portion of the implant without deforming. In thiscase, as element 18 is slid from the unlocked position to the lockedposition, it compresses the split portions, driving them toward oneanother and driving the protrusions 14P into the mating recesses 202.

Both element 12 and element 18 have slots or recesses (14S, 18Srespectively) that are configured to allow a stabilization element (suchas a rod, bar, plate or the like) received by implant 200 to also extendthrough the elements 12,18 of derotator member 10. Element 12 includes aslot 14L that is engaged by a pin 18P that extends inwardly into element18. Slot 14L functions as a track along which pin 18P slides, therebyensuring that recesses 14S, 18S align in the locked position, and alsoprevents element 18 from sliding off of element 12 if the assembly isinverted prior to attaching linking member 30 to element 12. In at leastone embodiment, slot 14L is a Z-shaped or L-shaped slot formed inelement 12 that is engaged by pin 18P.

Turning now to FIG. 3A, an isolated, perspective view of linking member30 is shown, according to an embodiment of the present invention. FIG.3B illustrates the linking member 20 of FIG. 3A engaged with thederotator member 10 shown in FIG. 2A. Linking member 30 includes aproximal end portion 30P and a distal end portion 30D. Distal endportion 30D includes an opening 32 configured and dimensioned to receivea proximal end portion of element 12 as described above. The matingkeyed inner surface 30M prevent rotations of the linking member 30relative to the elongate member 12/derotator member 10 once engagedtherewith as shown in FIG. 3B. Prior to that, the keying configurationshown allows selection from a plurality of different rotationalorientations of the linking member relative to element 12 as alreadydescribed above.

A locking element 34 is movable from a locked configuration (illustratedin the cross-sectional view of FIG. 3C) to an unlocked configuration,and vice versa. In the embodiment shown, a portion of the lockingelement extends out from the external surface of the distal end portion30D surrounding it, and can be pressed inwardly to move from the lockedconfiguration to the unlocked configuration In FIG. 3C, it is shown thatlocking element 34 is biased to the locked configuration by biasingmember 34B. When linking member 30 is mounted over the proximal endportion of element 12, the actuation surface 34A of locking element 34can be pressed inwardly so as to move the locking element 34 (move tothe left in FIG. 3C) to align its opening with the opening 32. However,pressing the actuation surface 34A inwardly during mounting is notnecessary, as the locking element 34 will self-align with the openingduring mounting. However, once locked into recess 16R, it is necessaryto press 34A to unlock the locking element 34. Thus, if pressed duringmounting, the actuation surface 34A can then be released and, as thelocking element 34 is moved distally past the distal most portion ofkeyed surface 16K and comes into alignment with recess 16R, biasingelement 34B drives a portion of the locking element 34 into recess 16R,thereby snapping it into place and axially locking linking member 30relative to element 12. This same process occurs automatically if thesurface 34A is not pressed and released during mounting. Linking member30 can be removed from element 12 by again depressing the actuationsurface 34A to unlock the locking element 34 and linking member can bereadily slid off the end of element 12.

Proximal end portion 30P includes an opening 36 configured and dimensionto receive and engage transverse member 40. Spikes, protrusions,knurling or other surface roughness 36K can be provided on the innersurface defining opening 36 so as to enhance friction between the innersurface and the transverse member 40 upon engagement therewith. Proximalend portion 30P is articulatable relative to the distal end portion inthree dimensions, when in an unlocked configuration. In the embodimentof FIGS. 3A-3D, proximal end portion 30P is connected to distal endportion 30D by a ball and socket joint arrangement 38, see FIG. 3D. Thisarrangement, in the unlocked configuration, allows rotation of proximalend portion by 360 degrees about the longitudinal axis L′-L′ of linkingmember 30 and allows tilting up to a maximum angle 37 of about 40degrees, typically the maximum angle is about 20 degrees, and in atleast one embodiment, the maximum angle may be about 15 degrees. Thisangulation, from zero degrees up to the maximum angle 37 can beperformed at any rotational position 360 degrees about the axis L′-L′.Thus, in an unlocked configuration, proximal end portion 30P isthree-dimensionally articulatable relative to distal end portion 30D.

Proximal end portion 30P further includes a driver 39 that is actuatableto releasably lock the transverse member 40 in engagement with linkingmember 30 after insertion of the transverse member 40 into opening 36.As shown in the embodiment of FIG. 3D, driver 39 includes a threadedshaft 39T that can be torqued into opening 36 to apply force againsttransverse member 40 when it is received therein, thereby locking theposition of transverse member 40 relative to proximal end portion 30P.At the same time, actuation of the driver 39 as described locks theproximal end portion 30P relative to the distal end portion 30D, as theball and socket joint is also locked and proximal end portion 30P can nolonger articulate relative to distal end portion 39D. Thus, transversemember 40, proximal end portion 30P, distal end portion 30D andderotator member 10 are all rigidly linked at this stage. Additionally,all of these rigidly linked components are also rigidly linked toimplant 200. Therefore, any movement of any component 40, 30P, 30D, 10,200 will cause movement of the vertebra in which the implant 200 isimplanted.

FIG. 4 is a longitudinal sectional view of an implant 200 that can beused according to an embodiment of the present invention. In thisembodiment, implant 200 is a pedicle screw, which can be a polyaxial,monoaxial or fixed screw. In the case of a polyaxial screw, the head 204of the implant can angulate relative to the longitudinal axis L″-L″ ofthe implant in the direction/plane of any transverse axis. A monoaxialscrew allows the head 204 to angulate relative to L″-L″ in only onetransverse plane and a fixed screw does not allow angulation of the head204 relative to the shaft 206. It is noted that this is exemplary onlyand that the present invention is not limited to any particular type ofimplant 200 used, or even to use of a pedicle screw, as other types ofimplants could be used as long as they have the capability of attachingto a vertebra with sufficient attachment force to move and manipulatethe vertebra, such as by rotation, without loosening or any otherfailure, and so long as they are configured to be engaged with andlocked to element 12.

FIG. 5 is a partial view illustrating derotator member 10 engaged withimplant 200. A portion of set screw 208 is visible as partiallyextending into the opening 210 formed in the head 204 of implant 200that is provided to receive a stabilization rod or the like. As notedabove, a tool can be inserted through element 12 to drive the set crew208 so as to lock the stabilization rod relative to the head 204 and/orto loosen it for repositioning. In addition, in cases where polyaxial ormonoaxial screws are used, the tool can also be inserted to drive setscrew 208 to lock or unlock the articulation capability of head 204relative to shaft 206.

In order to rigidly link multiple assemblies of the type shown in FIG.1, thereby rigidly linking multiple levels/vertebra of a spine to as tomanipulate in unison, an interlinking assembly can be provided to engagemultiple derotator assemblies and rigidly link them. FIG. 6A is aperspective view of an interlevel linking assembly 50 according to anembodiment of the present invention. Interlevel linking assembly 50includes an elongate interlink member 52 having a length sufficient tospan the locations of all of the derotator members 10 to be linked andhaving sufficient rigidity to transfers forces from one derotator memberto all derotator members 10 connected thereto, without any significantdeformation or loss of force. In the embodiment shown in FIG. 6A, theassembly 50 is provided to link four derotator members 10. However, thepresent invention is not limited to this number, as the conceptsdescribed here are readily adaptable to assemblies configured to linktwo, three, or more than found derotator members 10. A plurality ofinterlink clamps 54 are provided in the assembly 50 and are configuredto securely engage the derotator members 10.

Interlink clamp 54 includes clamp jaws 56 configured to releasablyengage the derotator member 10; a shaft 58 9see FIG. 6E) extending fromthe clamp jaws 56; and a driver 60 threadably actuatable on an end ofshaft 58 extending away from the clamp jaws 56 to actuate the clamp jawsto clamp down on the element 12 of derotator member 10. The shaft 58 hassufficient length to extend through an opening 52L in the elongateinterlink member 52 and engage the driver 60 on one side of elongateinterlink member 52 while clamp jaws 56 are positioned on an oppositeside of elongate interlink member 52, as illustrated in FIG. 6A. In thisregard, shaft 58 can be threaded 58T, for example and driver knob 60 canbe provided with mating threads so that driver knob 60 can be torquedagainst the interlink member 52. As the shaft 58 is drawn into thedriver knob 60 by torquing the knob 60 (with clamp jaws 56 beingprevented from rotating about the axis of shaft 58, as having beenengaged with element 12) this drives the base portion 62 of the driverassembly (since it is slidable relative to shaft 58) against clamp jaws56. The concave curvature of the base surface contacting the clamp jaws56 drives the clamp jaws into compression, causing them to securely andrigidly engage the element 12 of derotator member 10. At the same time,the clamp 54 becomes rigidly fixed relative to interlink member 52.Prior to actuating the driver 60, clamp 54 can slide along opening 52L(typically formed as a longitudinally extending slot) and can rotaterelative to the longitudinal axis of shaft 58 over a controlled range ofrotation. For example, the controlled range of rotation may have amaximum angle of rotation of up to about ±170 degrees, or a maximumangle of rotation as low as about ±10 degrees. Currently, the preferredmaximum angle of controlled rotation is about ±20 degrees, where theangle 41 is measured between the longitudinal axis of the elongateinterlink member 52 and the longitudinal axis of the base 62. Thus, theclamp is rotatable in either direction from an angle 41 of zero degreesup to and including the maximum angle of the controlled rotation range.Stops 62S are provided on the base member 62 which contact the interlinkmember 52 when the maximum angle 41 has been reached. Prior to actuatingthe driver, the clamp jaws are preferably configured and dimension toform a snap fit over element 12, so that they can be easily initiallyattached without the need for actuating the clamps.

In FIGS. 6A-6B, the elongate interlink member 52 comprises a rigid,unitary plate and both the plate and the slot 52L have a lengthsufficient to span all of the derotator members 10 to be linked. Inanother embodiment, as shown in FIGS. 6C-6D, elongate interlink member52 comprises a plurality of linked plates 52′. Linked plates 52′ areaxially rotatable relative to one another, within a controlled range ofrotation. Pins 64 are provided to interconnect the plates 52′ and plates52′ are rotatable about pins 64. Stops 66 are provided to limit theamount of rotation of one plate 52′ relative to an adjacent plate 52′The amount of rotation may be up to about ±30 degrees, typically up toabout ±15 degrees. The rotation allowed between links 52′ provides anadditional degree of freedom that can be useful to facilitate engagementof the assembly 50 with derotator members 10 having varyingorientations, as it is often the case that the members will not beparallel due to the misalignment of the vertebrae that they are attachedto. Additionally, clamps 54 can slide and rotate about a controlledrange of rotation while installed in the links 52′, prior to finalclamping through actuating the driver 60.

To still further facilitate the attachment of assembly 50 to multiplederotator members 10, clamps 54 of varying lengths may be provided. Thiscan address issues where derotator members 10 are located inorientations resulting in different distances from the plane of theinterlink member 52 during attachment. FIG. 6G illustrates threedifferent lengths of clamps 54 (i.e., 54A, 54B and 54C) where 54C has alength greater than 54B and 54B has a length greater than 54A. thevariations in length are established by the provision of actuator bases62 having varying length. In the embodiment of FIG. 6G. the length 62Lof base 62C is greater than the length of base 62B and the length ofbase 62B is greater than the length of base 62A. This also necessitatesthat the shaft 58 of 54C is longer than the shaft of 54B and the shaftof 54B is longer than the shaft of 54A. FIG. 6F is a longitudinalsectional view of claim 54.

FIG. 8A illustrates a system including four sets of assemblies of thetype shown in FIG. 1, attached to implants 200 implanted in fouradjacent vertebrae of a spine (four levels). FIG. 8B shows the system ofFIG. 8A after rigidly interlinking the assemblies using interlinkassembly 50 in a manner as described above. The system is shown linkedby an interlink assembly 50 attached to one side of the system and thisis currently the preferred practice. However, the invention is notlimited to this embodiment, as the assembly 50 could be attached to theopposite side, or tow assemblies 50 (one on each side) could beimplemented. Still further, multiple assemblies 50 can be used on oneside. For example, one assembly 50 could be engaged to link two adjacentmembers 10 and a second assembly 50 could be engaged to link two othermembers 10.

FIG. 7 is a plan view of a handle 70 that can be employed as part of asystem according to an embodiment of the present invention. Handle 70 issufficiently rigid in bending strength to be used to apply moments offorce to the assembly 300 without plastically deforming. Handle 70 hassufficient torsional rigidity to allow it to be used as a driver tool Afirst end of tool 70 comprises a socket 72 configured to mate with atleast one of driver 39 and driver 60. Preferably, driver 39 and driver60 are configured with the same shape and dimensions so that handle 60can be used to engage and drive both driver 60 and driver 39.Additionally, one or more handles can be engaged to driver 39 and/ordriver 60 to apply moments of force to the system 300 to manipulate thespine. However, it is preferred to apply force through the oppositeend(s) of the handle(s) 70 by engaging them in the opening(s) 16P asdescribed hereafter. The opposite end 74 of tool 70 is configured anddimensioned to be received in and mate with proximal opening 16P ofelement 12. Upon such mating, moments of force can be applied toderotator member 10 through handle 70 and element 12. Handle 70 isenlarged in the central portion to form a more comfortable fit to thehand of a use and provide more mechanical advantage when rotating todrive the socket end 72. The central portion may also be knurled,scalloped or otherwise contoured 76 to enhanced friction between thehandle and the hand of the user.

FIG. 9A illustrates system 300 with one handle 70 attached, wherein end74 is inserted into opening 16P of one of the derotator members. FIG.9B. illustrates system 300 with two handles 70 attached, wherein end 74of one handle 70 is inserted into opening 16P of one of the derotatormembers and end 74 of the other handle is inserted into opening 16P ofthe other derotator member attached to the same level. FIG. 9C.illustrates system 300 with one handle 70 attached, wherein end 72 ismated over one of the drivers 60 of interlink assembly 50. It is notedthat FIGS. 9A-9C are only exemplary, as handles 70 can be engaged withany combination of openings 16P, drivers 30 and drivers 60.

FIGS. 10A-10I illustrate a method of assembling the assembly of FIG. 1to establish derotator triangulation. Assembling a system 300 can beperformed by assembling multiple assemblies in the manner described hereand interlinking the assemblies using one or more interlevel linkingassemblies as described above. At FIG. 10A, derotator members 10 areadvanced toward the heads of the implants 200 having been implanted invertebra 2. It is noted here that although both sides are beingaddressed by a single description, the components do not have to besimultaneously assembled on both sides, but can instead, be assemblysequentially. At FIG. 10B, the protrusions 14P have engaged the recesses202 after forcing the distal ends of the derotator members 10 over theheads of the implants 200. In FIG. 10C, elements 18 (outer sleeves) areslid distally over the split portions 14 to lock the derotator members10 to the implants 200. FIG. 10D illustrates an optional feature inwhich a visual indicator 18V (such as a laser-etched arrow or otherreadily visually identifiable indicator) is provided on element 12 andbecomes visible when element 18 has been slid distally sufficient toproperly align the distal end of element 18 with the distal end ofelement 12.

In FIG. 10E the linking members 30 are locked to the derotator members10. As noted above, in at least one embodiment it is possible to engagethe linking member in different rotational orientations relative to thederotator member. The linking members 30 should be oriented such thatwhen transverse member 40 is engaged with the openings 36, thetransverse member 40 does not obstruct the openings 16P. This isimportant as access to openings 16P must be kept open to allowinsertions of tools and/or handle 70. FIGS. 10F and 10G are top and sideviews, respectively, illustrating an assembly in which linking members30 have been oriented in acceptable positions relative to derotatormembers 10, where it is shown that openings 16P are readily accessible.In contrast, FIGS. 10F′-10G′ are top and side views, respectively,illustrating an assembly in which linking members 30 have beenimproperly oriented relative to derotator members 10, so that transversemember 40 obstructs the openings 16P making it impossible to access theopenings 16P with a tool or handle 70.

Upon inserting the transverse member, the proximal end portions 30P oflinking members 30 can be articulated three dimensionally, such that notonly can the proximal end portions 30P and transverse member be tiltedtoward the head of the patient or the foot of the patient, but they canalso be tilted left or right, or in some angular direction in between.In FIG. 10H, after the transverse member 40 has been inserted intolinking members 30 and the transverse member 40 and lining member 30have been articulated relative to derotator members 10 if necessary, oneor more handle(s) is/are used to actuate the drivers 39 to lock thetransverse member 40 relative to proximal end portion 30P and to lockthe proximal end portion 30P relative to distal end portion 30D. In FIG.10I, the opposite end 74 of tool 70 is inserted into opening 16 p ofderotator member 10 and force is applied through handle 70 to causerotation of the assembly and the vertebra as illustrated in phantom.

FIG. 11 illustrates a tool 400 being used to tighten a set screw 208 ofimplant 200 to lock the orientation of the implant 200 relative to astabilization rod 500. The working end or distal end portion of the tool400 has been inserted into opening 16P and through element 12 tointerface with the set screw 208 and the set screw is torqued by turninghandle 402 of tool 400.

While the present invention has been described with reference to thespecific embodiments thereof, it should be understood by those skilledin the art that various changes may be made and equivalents may besubstituted without departing from the true spirit and scope of theinvention. In addition, many modifications may be made to adapt aparticular situation, material, composition of matter, process, processstep or steps, to the objective, spirit and scope of the presentinvention. All such modifications are intended to be within the scope ofthe claims appended hereto.

That which is claimed is:
 1. A derotator member useful in a system forcorrecting alignment of one or more vertebrae of a spine, said derotatormember comprising: a first elongate element having a first proximal endportion and a first distal end portion, said first distal end portionbeing configured to releasably engage with an implant implanted in oneof the vertebrae; and a second elongate element slidable over said firstelongate element, said second elongate element having a second proximalend portion and a second distal end portion, said first proximal endportion comprising a keyed outer surface having a non-circularcross-sectional shape and a largest cross-sectional dimension less thanor equal to a smallest cross-sectional inside dimension of said secondelongate element; a protrusion extending from one of said first andsecond elongate elements; and a slot formed in the other of said firstand second elements; wherein said protrusion is received in said slotwhen said second elongate element is slid over said first elongateelement.
 2. The derotator member of claim 1, wherein an end portion ofsaid slot cooperates with said protrusion to prevent said secondelongate element from sliding off and separating from said firstelongate element when said first and second elongate elements areinverted.
 3. The derotator member of claim 1, said first distal endportion of said first elongate element comprising first recessed slotsconfigured to allow a stabilization element received by the implant toextend therethrough; and said second distal end portion of said secondelongate element comprising second recessed slots configured to allowthe stabilization element received by the implant to extendtherethrough; wherein, upon sliding said second elongate elementrelative to said first elongate element, said slot functions as a trackalong which said protrusion slides, thereby ensuring that said secondrecessed slots align with said first recessed slots.
 4. The derotatormember of claim 1, wherein said distal end portion of said firstelongate element is longitudinally split into at least two first splitportions configured to releasably engage with the implant.
 5. Thederotator member of claim 1, wherein said protrusion extends inwardlyfrom an inner wall of said second elongate element and said slot isformed in an outer wall of said first elongate element.
 6. The derotatormember of claim 1, wherein said slot is Z-shaped or L-shaped.
 7. Thederotator member of claim 1, wherein a distal end of said second distalend portion is beveled.
 8. The derotator member of claim 7, wherein saidfirst elongate element comprises a necked portion comprising a firstcircumference smaller than a second circumference characterizing aportion of said first elongate element distal of said necked portion;and wherein a portion of said first elongate element intermediate ofsaid necked portion and said portion having said second circumference isbeveled for interaction with said beveled distal end of said seconddistal end portion.
 9. A derotator member useful in a system forcorrecting alignment of one or more vertebrae of a spine, said derotatormember comprising: a first elongate element having a first proximal endportion and a first distal end portion, said first distal end portionbeing longitudinally split into at least two split portions configuredto releasably engage with an implant implanted in one of the vertebrae;a second elongate element slidable over said first elongate element,said second elongate element having a second proximal end portion and asecond distal end portion; and said first proximal end portioncomprising a keyed outer surface having a non-circular cross-sectionalshape and a largest cross-sectional dimension less than or equal to asmallest cross-sectional inside dimension of said second elongateelement; wherein said second distal end portion is slidable over atleast part of said split portions thereby preventing said split portionsfrom deforming away from one another; and wherein said second distal endportion is slidable away from said split portions to an extent to allowsaid split portions to deform away from one another.
 10. The derotatormember of claim 9, wherein said keyed outer surface is formed at aproximal end of said first proximal end portion.
 11. The derotatormember of claim 9, wherein said keyed outer surface is multifaceted andcomprises more than two facets.
 12. The derotator member of claim 9,wherein said keyed outer surface comprises two multifaceted surfacesseparated by a recess.
 13. An assembly useful in a system for correctingalignment of one or more vertebrae of a spine, said assembly comprising:a derotator member comprising: a first elongate element having a firstproximal end portion and a first distal end portion, said first distalend portion being longitudinally split into at least two split portionsconfigured to releasably engage with an implant implanted in one of thevertebrae; a second elongate element slidable over said first elongateelement, said second elongate element having a second proximal endportion and a second distal end portion; and said first proximal endportion comprising a keyed outer surface having a non-circularcross-sectional shape; wherein said second distal end portion isslidable over at least part of said split portions thereby preventingsaid split portions from deforming away from one another; and whereinsaid second distal end portion is slidable away from said split portionsto an extent to allow said split portions to deform away from oneanother; and a linking member for linking the derotator member to atransverse member, said linking member comprising: a third distal endportion and a third proximal end portion; said third distal end portioncomprising an opening having a keyed inner surface configured to matewith said keyed outer surface of said first proximal end portion, saidkeyed inners surface being multifaceted and permitting selection frommore than two different angular orientations of said linking memberrelative to a transverse axis of said derotator member, wherein saidlinking member is maintained in a selected angular orientation onceengaged with said derotator member at the selected angular orientation.14. The assembly of claim 13, wherein said third proximal end portioncomprises a second opening configured to receive and reliably engagewith the transverse member.
 15. The assembly of claim 13, wherein saidlinking member further comprises a locking element configured toreleasably lock said linking member to said derotator member.
 16. Theassembly of claim 15, wherein said locking element is movable from alocked configuration to an unlocked configuration and vice versa,wherein, when in said locked configuration, said locking element extendsinto said opening of said distal end portion.
 17. The assembly of claim13, wherein said third proximal end portion is articulatable relative tosaid third distal end portion.
 18. The assembly of claim 13, whereinsaid third proximal end portion is articulatable relative to said thirddistal end portion in three dimensions.